Tezontepec (Smn) Weather Records (MXN00013035)

The annual mean temperature here has risen by 0.3 C (0.2 to 0.5) per decade over 1943 to 2008. In Fahrenheit: 0.6 F (0.4 to 0.9) per decade. The slope is a straight line fitted to 60 complete years; the brackets give its 95 percent interval.

Across 56 years with a frost, the median last spring frost at Tezontepec (Smn) falls on 1 April and the median first autumn frost on 23 October, which leaves a median of 207 days between them.

Fitted over all years, the growing season changes by +13.7 days per decade at this station.

A day with at least 37.2 mm (1.5 in) of rain is expected about once in 2 years. A day with at least 66.6 mm (2.6 in) of rain is expected about once in 100 years.

The levels come from a generalised extreme value (GEV) distribution fitted by L-moments to the wettest-day total of each year, 60 years of values from 1943 to 2008.

A return level is an estimate. It is least reliable for the long periods, 50 and 100 years, and for any period longer than the record behind the fit, where the fit has to reach past the largest day actually observed. It is not a forecast.

The largest wettest-day totals in the fit: 68.6 mm (2.7 in) in 2007; 65.3 mm (2.6 in) in 2008; 63.8 mm (2.5 in) in 1992.

One change was suspected in the annual mean temperature of Tezontepec (Smn), at 1999. Each is measured against neighbouring stations.

• Relative to 5 neighbouring stations, the station's annual mean temperature from 1999 ran 0.9 C (1.5 F) higher than in the years before (possible change).